(1) Field of the Invention
This invention relates generally to toner removal systems in electrophotographic printing machines and specifically to a method for making a toner removal brush with improved properties.
(2) Description of the Prior Art
By definition, electrophotographic printing comprises the steps of (1) charging a electrophotographic surface, e.g., of selenium, tellurium, palladium, with a static voltage of about 3,000 volts (2) shielding the selenium surface, such as a plate, with a light pervious layer carrying an opaque image that is to be recorded (3) exposing the combination to a light source that is directed through the shield to the electrophotographic surface photoreceptor, or drum or plate whereby all the parts of the surface not covered by the opaque image give up their charge (4) dusting (i.e., developing) the plate with carbon or other powder toner (the toner will adhere to the charged portions) and (5) transferring the toner image to paper through the application of an electrostatic field.
This it is well recognized that electrophotography or "dry printing" requires the application of a pigmented powder on to the surface of a charged plate (the photoconductor) in order to develop the latent electrostatic images thereon. Thus toner removal becomes quite important if one is to accomplish both the substantial removal of all the toner from the photoconductor drum and at the same time, protect the longevity of the photoconductor drum, as well as the life of the brush.
In the prior art for example, cleaning brushes or wipers are used in drycopying machines or duplicators where such wipers are in contact with the image transferring masters made out of or coated with photoconductive materials and such wipers or brushes attempt to serve the purpose of removing the residual latent image from the photoconductor without damaging or destroying the photoconductor itself. So far this has not been fully accomplished in the prior art and the brush fiber ends retain fused toner and/or either become clogged with toner material after relatively few turns of the brush against the photoconductor (the brush develops the same charge as the photoconductor, such charge arcing over toner particles and fusing the toner); or the brushes are made such that they scar and damage the photoconductor drum. Representative U.S. patents in the art of xerography and toner removal, just to name a few, include Nos. 2,297,691; 2,859,673; 2,911,330; 2,944,147; 2,959,153; and 3,093,039.